Professor Jonathan Gould talks about his recent article, Law Within Congress. Recognizing that procedure has long shaped how Congress operates—from bills about civil rights to tax policy to presidential impeachments—this article explores parliamentary precedent in Congress. These precedents constitute a hidden system of law that has received little scholarly attention, despite being critical to shaping what goes on in Congress. Understanding parliamentary precedent requires understanding the institutional positions of the parliamentarians, the nonpartisan officials who resolve procedural disputes. Drawing on novel interviews with parliamentarians and the legislative staffers who work closely with them, this article illuminates the intersection of law and politics in the making of parliamentary precedent. A better understanding of parliamentary precedent contributes to our understanding of how Congress operates, and the fault lines that emerge in an age of polarization and hardball. These dynamics also hold lessons for public law more broadly.